686556 has 60 divisors (see below), whose sum is σ = 1944712. Its totient is φ = 209952.

The previous prime is 686551. The next prime is 686563. The reversal of 686556 is 655686.

686556 = 24² + 25² + ... + 127².

It is a super-3 number, since 3×686556³ = 970843339505302848, which contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (36).

Its product of digits (43200) is a multiple of the sum of its prime factors (192).

It is a self number, because there is not a number n which added to its sum of digits gives 686556.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686551) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 4131 + ... + 4293.

2⁶⁸⁶⁵⁵⁶ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 686556, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (972356).

686556 is an abundant number, since it is smaller than the sum of its proper divisors (1258156).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

686556 is a wasteful number, since it uses less digits than its factorization.

686556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192 (or 181 counting only the distinct ones).

The product of its digits is 43200, while the sum is 36.

The square root of 686556 is about 828.5867486268. The cubic root of 686556 is about 88.2182941366.

The spelling of 686556 in words is "six hundred eighty-six thousand, five hundred fifty-six".